The official Prima Games Guide for Super Mario Galaxy was released in two editions: the Premiere Edition and the Collector's Edition. Among the features included in the Collector's Edition were six pages of concept art and beta info from the game's developers.

Rosalina was intended to be related to Princess Peach. They have very similar appearances, reflecting this. Bonefin Galaxy was intended to be much darker, as was Deep Dark Galaxy. These were changed in the interest of playability. Guppy was originally a dolphin, and a friendly character. Some art of the Sea Slide and Beach Bowl Galaxies suggests that they were conceived as a single galaxy, with Beach Bowl's main planet in the center of Sea Slide's ring. A piece of concept art labeled only "fortress" is captioned as a piece that is very memorable to the SMG development team, since it was one of the earliest drawings of Galaxy. Ironically, the planet shown in the art is nowhere in the final game.

E3 2006 was the first event in which Nintendo publicly showed Galaxy in anything akin to its final form, although it was quite different from the final game. In this prototype build, attendees were treated to a single-galaxy demo of the game, in which they were given ten minutes to find and collect a star. This build had many differences from the final game, although all the basic principles of the game existed in some form.

Some game mechanics eventually changed:

Mario had the ability to spin to attract coins to him, which he lost in the final version. He can still do this as Flying Mario and underwater.

In this version of the game Mario could spin multiple times in a row. In the final version, a small delay is enforced during Spins.

In this prototype, players had to hold and point at Star Bits to grab them. This was later changed because the developers settled on using the button to fire Star Bits (which was impossible at this point.)

Mario could kick Star Bits around.

Mario's Star Cursor was more powerful. It had many of the powers given to the Second Player's cursor in the final game, such as holding enemies.

The Life Meter was more like the one in Super Mario 64, having a total of eight health, and changing color more like the Super Mario 64 version. This was changed to three wedges in the final version.

At this point, Rainbow Notes had an on screen counter, showing players how many musical notes they had collected, as well as how many there were total.

Here, if a player wanted to use a Pull Star (or what would eventually be called a Pull Star), he or she would need to point at it constantly, as moving the star cursor would deactivate it. In the final game, the Pull Star will remain active until players release the button.

If a character wanted to talk to Mario, an exclamation point in a thought bubble would appear above its head. When Mario got close to that character, its dialogue would appear onscreen without interrupting gameplay.

When the player pulled on a sling pod a white arrow will show the direction Mario is going to go, also if the player pulled too long the arrow will turn red.

When the player grabbed a coin, the coin sound effect can be heard on the Wii Remote's speaker.

When the player attacked a Goomba, it did not spin after being launched.

Some graphics were not complete, or were different:

The Star Bit Counter said 0/100 in this version. No attendee to E3 collected all 100 of the galaxy's "Star Shards" (as they were then known), so their purpose is unknown.

The Star Cursor was yellow in color, and it had a longer "tail." It flashed red if players were not pointing the Wii remote at the screen.

The message "You Got a Star!" was white, and written in all caps. This is changed to green in the final version. The "Too Bad!" text was the same but it later changed to red letters in the final version.

The HUD effects for using a Sling Pod were different. These can be seen in the Tarantox videos.

The Mario head used as a lives counter was captioned "MARIO."

The HUD design used the number font from Super Mario Sunshine.

One-ups used a simpler, green "1up!" effect when collected.

Certain sound effects were substituted out for others, usually because not all sound composition was complete:

When Mario grabbed a star, the music was a remix of the goal tune from the original Super Mario Bros..

Super Mario Sunshine voices were used as Mario's voice as a placeholder.

Star World was the demonstration galaxy created to show off Super Mario Galaxy for E3 2006. It was comprised of many planets taken from other galaxies in the game. It was notably different from any galaxy in the final game in that it was comprised of a "branching" path- choosing different routes on different planets could lead to different stars entirely. It was also notable for its heavy use of asteroids instead of unique planets. The final game ended up using these asteroids only twice, as moons in two galaxies.

This galaxy was inhabited by rabbits and the conjecturally named Cosmic Toads, who were distinguished from normal Toads by the star shaped spots on their caps. They gave players hints and explained the controls. Sometimes, the rabbits could change into Cosmic Toads. Their role was likely replaced by Lumas. They explained various aspects of the game to Mario.

Since this galaxy was compiled into a build that allowed Mario's Star Cursor to hold enemies, some of its puzzles made use of that[3].

Snifit Bot was notably different from the final game's Megaleg. It was not commanded by Bowser Jr, and not powered by a Star. The weak point started out blue, and became red once the outer protective layer was broken (In the final game, it starts out white, then turns pink.) Also, the rotating light source is inside the glass dome on top of Snifit Bot, as opposed to on top of it. Megaleg has a small depression on the top of its head, which Snifit Bot did not. Snifit Bot had three coins near each of the two metal patches on its head, and two coins on each leg, making the battle somewhat easier for players. After it was hit for the first time, it guarded its weak point with four unbreakable walls, rather than eight breakable ones. When Snifit Bot is killed, its head smokes, which does not happen to Megaleg. Snifit Bot guarded a normal Star, as opposed to a Grand Star.It also has spikes on it's legs which are gone in the final game.

Tarantox was also different, though not nearly as much so as Snifit Bot. Attacking any of the fluid filled green sacs on it was enough to flip it over, while in the final game, only the large one on its bottom is sufficient. Once the red sacs on its belly have been destroyed one time each, the final version's Tarantox will regrow all of the green sacs. Not so for Star World's Tarantox. The red sacs on Star World's Tarantox also pulsate more, and with a higher pitched sound effect.

King Kaliente's battle was almost identical to his battle in the released game. The only difference observed is that the flaming projectiles he shot could be batted away with the star cursor. However, not many videos of King Kaliente were released.

All three bosses did not release Star Bits when attacked, since there were only 100 Star Bits in the whole galaxy. However, no attendee to the show ever collected all of them, so their purpose remains unknown (they could not be fired at enemies as they are in the final game).

It is notable that every planet in this galaxy would eventually make it into the final game (although some were modified heavily), with one exception. The planet players started on, (not officially named, but called "HomePlanet" internally by the game) is totally absent from the final game, although its model data is still present.

The planet just before Megaleg/Snifit Bot's planet originally had a grassy (as opposed to metallic) design. A minor glitch in the released game causes the grassy version of this planet to appear if players stand on top of Megaleg and look at the metallic version. This is caused by an incorrectly set-up culling method. When the planet was redesigned, its low-poly model was not. The series of planets leading up to Tarantox is significantly more decayed than the same planets in the final game. The same is true of Captain Olimar's ship. The first planet from Good Egg Galaxy is shown in a much different form here. Additionally, the planet with rolling boulders and mud from Good Egg Galaxy appears here, but without the mud, or the puzzle that would accompany it in the final game.

Although called "Star World" by fans, this name is taken from the "Welcome to the Star World!" message that appeared when starting this galaxy. Based on the similar message used in the final game, it could just be a mistranslation of "galaxy".

The music that plays in this galaxy is known as "Egg Planet." It is the theme of Good Egg Galaxy in the final game.

When Mario falls into a black hole, he has an oval like line.

Mario and the mission to find the musical notes.

"HomePlanet", never to be seen in the final version. (Cosmic Toads can be seen.)

The Launch Star on top of Good Egg Galaxy's tower is lower, and the planet it leads to lacks the pools of mud and Star Chips that it has in the final game. (This is also the design of this planet that was featured in Star World)

The second early Life Meter

A second design of the Health Meter was used, this one identical to the first except with the green and blue colors swapped.

A few planets from Gusty Garden Galaxy were in Good Egg Galaxy at this point, including the apples. It is possible that they were one galaxy at this point.

An area appears in the video in which there are many sinking platforms above lava. Though this area has many coins in the video, they have all become Star Bits in the final game. The final game's Lumalee is also missing.

Since E3 was downsized to the E3 Media and Business Summit in 2007, less Galaxy info was released than in 2006. The first Galaxy related content was a press conference video, which was very close to the final game.

Later on, attendees were allowed to play a demo of the game, from which they had access to Good Egg Galaxy, Honeyhive Galaxy, and Space Junk Galaxy. The press conference video above is not from this demo, but from a very slightly earlier build of the game[9]. Some videos taken by attendees reveal differences from the released game.

The "Space Junk Galaxy" was called "Star Dust Galaxy." This is also the galaxy's name in the Japanese version.

The first star of that galaxy was called "The Beam Star Trail" ("Pull Star Path" in the final game.)

Thus, "Pull Stars" were known as "Beam Stars."

In the opening movie to a galaxy, the name of the current star is printed at the top of the screen, while the galaxy's name is at the bottom. In the final game, both are at the top, with the star's name below the galaxy's name.

Here, the message "Point at the screen with [the Wii Remote]" is aligned with the left side of the screen, rather than centered. "Aim at [the beam star] and press [A]." is similar.

One coin featured in this demo version is missing from the final game.

In all versions of the guide, readers are advised to look for a "unicorn-like horn" on the floor of the Bonefin Galaxy's main planet, since there is a red shell near it. The guide even shows a picture of the aforementioned. However, it is totally absent from the final game, suggesting that some modifications were made to the game even after it was given to the guide's writers.

Ticojii, a character resembling Eldstar. Its name is probably a derived from the Japanese words チコ tiko, meaning "Luma" and お祖父さん ojīsan, meaning "grandfather" or "old man".

Onitsutsu[15], which would appear to be a type of Tox Box. It has the Japanese character 鬼 oni on one face[16], referring to the Oni from Japanese folk lore. The second half of its name is probably from the word 筒 tsutsu, meaning tube.

Billboarder, a small humanoid figure made out of flat circular textures with over fifty animations.

The model for the "fortress" from the Prima Guide's concept art page exists in the data, as well as the large Megaleg-like figure below it, which is known as "BossCrab".

"BossCrab" itself, a 4-legged version of what would become Megaleg, all of it's animation exists.

A very early version of the music note model with a wiggling animation.

DragonHeadFlower[17], a gigantic Piranha Plant-like enemy. It has animations for eating Mario/Luigi and spitting him back out.

A humanoid creature made of ice, called IceMan[18]. It has animations such as AngryDemo and DeathDemo, indicating it was possibly some kind of boss. Also included is a model for the ice chunks that it would throw at the player.

OtaJack, a large green octopus whose name and appearance indicate it is related to King Kaliente (known as OtaKing in the game's data). It has animations for waiting and being picked up. It is also vaguely similar to Prince Pikante from the sequel.

A massive sand golem whose main model only contains skeleton and animation data, being built out of individual segments known as SandGolemBlock and SandGolemColumn.

TetuKuri, a shiny grey Goomba whose name translates to "Iron Goomba". It lacks animations for getting hit by a spin attack, indicating that it would be immune to it.

SpiderItemShell, a strange yellowish ball that opens up like the Party Ball from the Smash Bros. series. Its file name coincidentally relates to the Beady Long Legs from the Pikmin series, a spider-like creature whose head resembles and opens up like a Party Ball.

A set of strange, grotesque insect-like creatures. The fact that the butterfly used in the game uses similar textures indicates that they were possibly intended for this game.

Jiraira, a black landmine with a Bowser emblem on it. Like Eyed Mines, it too can regenerate after detonation.

The low-polygon model for the house in Ghostly Galaxy has two chimneys that the high-polygon model lacks.

An early model of Buoy Base Galaxy. It has more platforms than the final design.

If a player uses hacks to leave the cave in Deep Dark Galaxy's Purple Coin star, they will find that the objects outside the cave are mostly gone or misplaced[24]. These oddities include:

The entire Toad Brigade is present, even though they are also in the cave with the purple coins.

Toad is on the beach, and he says the Green Toad's normal message (Nope, I don't see any Purple Coin(s) hidden in the dirt.)

The Yellow Toad is also on the beach, standing on top of a blue structure only found on some levels in the Sea Slide Galaxy. He will create an empty text box if spoken to.

The Green Toad is dancing where the Blue Toad stood during star 2.

The Blue Toad is inside the titular box of the "Boo in a Box" star. He floats above the ground and does not have glasses. If Mario gets too close to him, he will create an empty "small" text box.

The Purple Toad is standing next to Toad, and he gives his normal message for that star, which makes no sense when read out of context.

There is a green pipe on the beach next to Toad and the Purple Toad. It is connected to another green pipe next to the Blue Toad. This could be an early route to the "Boo in a Box" star, or it could simply be an aid for testing.

Next to the Green Toad there is a series of climbable poles. One of these is tilted at an odd angle an does not lead anywhere significant.

Early in development, a planet known as "Starman Fort" was to be included in the game. The planet was comprised of a large castle-like structure, as well as a construction zone. The zone contained a boss that is referred to as "Boss Crab". It is thought that it is an early version of Megaleg.

An unused section of the Bubble Blast Galaxy contains cube bubbles. The only section of land is a small metal platform. The area is heat-based, and contains such obstacles as fireballs, wind, and steam. The level is designed in a maze format.